1. Field of the Invention
This invention relates in general to the construction of switches and in particular to a new and useful electrical switch having a locking mechanism for the actuating member which is mounted on the outside of the switch housing.
2. Description of the Prior Art
The present invention relates to an improved construction for electrical switch which has a locking mechanism for the actuating member of the switch. The known switches of this kind are of two general designs: In one of the designs the locking mechanism prevents an unintentional actuation of the switch and such mechanisms are used for example in electrically operated hand tools such as grinding, boring and similar tools. If such a tool is inadvertently laid down on its actuating member it may be started in a completely uncontrolled manner and this may lead to considerable accidents. On the other design the locking mechanism serves to retain the switch actuating member in its on or off position and for example to lock a button in its actuated position. Here again the field of application for such devices is generally for hand operated tools. In all of the known switches of this kind the actuating member projects at one location and the locking member projects at another location of the switch housing. Somewhere in the interior of the switch the two members can be interlocked. The disadvantage of such switches is that dust, moisture or the like can penetrate into the switch housing at the two locations. On the other hand up to date dust proof or dust tight switches are demanded more and more. If such switches are to be provided with additional locking mechanisms two sealing arrangements are necessary and such switches become very expensive to manufacture.